The /boot partition holds critical files needed during the Linux boot process, including:

• Kernel images (vmlinuz-*)
• Initial RAM disk images (initrd-*)
• Bootloader configuration files (grub.cfg)
• System.map files

# Typical /boot directory structure
/boot/
├── grub/
│   ├── grub.cfg
│   └── fonts/
├── initrd.img-5.4.0-42-generic
├── vmlinuz-5.4.0-42-generic
└── System.map-5.4.0-42-generic

Usage Scenario	Recommended Size	Rationale
Standard desktop/server (UEFI)	500MB-1GB	Accommodates multiple kernel versions and initramfs
Legacy BIOS systems	200-500MB	Smaller footprint but limited to 2TB disks
Embedded systems	50-100MB	Minimal kernel requirements

A dedicated /boot partition becomes necessary when:

• Using full-disk encryption (LUKS)
• Bootloader cannot access root filesystem (e.g., ZFS, Btrfs, XFS)
• Implementing RAID/LVM configurations

Using fdisk for /boot Partition

# fdisk /dev/sda
Command (m for help): n
Partition type: p
Partition number: 1
First sector: 2048
Last sector: +500M

Command (m for help): t
Selected partition 1
Hex code: EF00  # for EFI system partition

Filesystem Formatting

# For UEFI systems
mkfs.fat -F32 /dev/sda1

# For legacy BIOS
mkfs.ext4 /dev/sda1

Regularly check partition usage with:

df -h /boot
du -sh /boot/*
ls -lh /boot/vmlinuz*

This bash script helps maintain /boot space by removing old kernels:

#!/bin/bash
CURRENT=$(uname -r)
OLD_KERNELS=$(dpkg -l | awk '/linux-image-[0-9]/{print $2}' | grep -v $CURRENT)

for kernel in $OLD_KERNELS; do
    sudo apt-get purge -y $kernel
done

sudo update-grub

AWS EC2 instances typically allocate 1GB for /boot because:

1. They maintain multiple kernel versions for rollback
2. Cloud-init stores temporary files during provisioning
3. Provides buffer for future kernel updates

Error: grub-install: error: cannot find EFI directory
Solution: Ensure /boot is mounted before GRUB installation:

mount /dev/sda1 /boot
grub-install /dev/sda

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The /boot partition stores critical files needed for system booting, including:

• Kernel images (vmlinuz-*)
• Initial RAM disk images (initrd-*)
• Bootloader configuration files (GRUB)
• System map files

For modern Linux distributions (2023+), these are the recommended sizes:

# Check current /boot usage (run as root)
du -sh /boot
df -h /boot

Scenario	Recommended Size
BIOS/MBR systems	200-500MB
UEFI systems (minimum)	500MB
Systems with multiple kernels	1GB
Enterprise servers	1-2GB

Modern Linux installations often don't require a separate /boot partition when:

• Using UEFI with GPT partitioning
• The root filesystem is ext4/XFS (not LVM or encrypted)
• System uses GRUB2 bootloader

For automated partitioning in kickstart files:

# Example kickstart configuration
part /boot --fstype=ext4 --size=512
part / --fstype=xfs --size=20480
part swap --recommended

For manual partitioning with fdisk:

# Create 1GB /boot partition
fdisk /dev/sda
n (new partition)
p (primary)
1 (partition number)
(default first sector)
+1G (size)
w (write changes)

Common solutions when /boot fills up:

# Remove old kernels (keep at least 2)
sudo apt autoremove --purge # Debian/Ubuntu
sudo dnf remove $(dnf repoquery --installonly --latest-limit=-2) # RHEL/Fedora

# Alternative manual cleanup:
ls /boot | grep vmlinuz
sudo rm /boot/vmlinuz-5.4.0-42-generic
sudo rm /boot/initrd.img-5.4.0-42-generic

Best practices for /boot filesystem:

• Use ext4 (most compatible)
• Avoid advanced features like LVM or encryption
• Keep on primary storage (not network/NFS)
• For UEFI: FAT32 for ESP (EFI System Partition)

In cloud environments (AWS, Azure, GCP):

• Most cloud images don't use separate /boot
• Kernel updates handled through cloud-init
• ESP partition still required for UEFI instances